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Infravermelho na caracterização de ácidos húmicos de latossolo sob efeito de uso contínuo de lodo de esgoto; Infrared spectroscopy in the characterization of humic acids from an oxisol under the effect of continuous use of sewage sludge

DIAS, Bruno de Oliveira; SILVA, Carlos Alberto; SOARES, Emanuelle Mercês Barros; BETTIOL, Wagner; GUERREIRO, Mário César; BELIZÁRIO, Maísa Honório
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica
POR
Relevância na Pesquisa
36.35%
Objetivou-se caracterizar, por meio de espectroscopia no infravermelho com transformada de Fourier (IVTF), possíveis mudanças na natureza química de ácidos húmicos (AHs) extraídos de amostras de Latossolo (0-10 cm) do Campo Experimental da Embrapa Meio Ambiente, em Jaguariúna (SP). Os dados foram obtidos após seis cultivos de milho e a aplicação de doses variáveis de lodo de esgoto de Barueri (LB) (base seca), conforme os tratamentos avaliados: LB0, LB1, LB2, LB4 e LB8, sendo 0, 1, 2, 4 e 8 vezes a necessidade de N para o milho. Como referência, foi amostrada uma área sob mata. Foram obtidos espectros de ácidos húmicos e do lodo de esgoto utilizado no experimento, e calculados os índices de hidrofobicidade (IH) e de condensação (IC) nas amostras de ácidos húmicos. Foram notadas pequenas alterações na natureza química de AHs de áreas tratadas com lodo de esgoto, em relação à testemunha. Os AHs apresentam grupos aromáticos, -OH fenólicos, -COOH, estruturas alifáticas, carboidratos e impurezas minerais. O uso contínuo de elevadas doses de LB reduziu a concentração de C-alifático e o grau de condensação dos ácidos húmicos, o que sinaliza que há frações orgânicas com maior biodisponibilidade no solo. Na área de mata...

Characterization of humic substances in salt marsh soils under sea rush (Juncus maritimus)

SANTIN, C.; GONZALEZ-PEREZ, M.; OTERO, X. L.; VIDAL-TORRADO, P.; MACIAS, F.; ALVAREZ, M. A.
Fonte: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD Publicador: ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.35%
Humic substances (HS) from salt marsh soils were characterized and the relationships among HS composition and some geochemical factors were analysed. For this, three salt marshes with the same vegetation cover (Juncus maritimus), but with different geochemical characteristics, were selected. The qualitative characterization of the soil humic acids and fulvic acids was carried out by elemental analysis, FTIR spectroscopy, fluorescence spectroscopy and VACP/MAS (13)C NMR spectroscopy. HS from salt marsh soils under sea rush (Juncus maritimus) displayed some shared characteristics such as low degree of humification, low aromatic content and high proportion of labile compounds, mainly polysaccharides and proteins. However, although the three salt marsh soils under study were covered by the same type of vegetation, the HS showed some important differences. HS composition was found to be determined not only by the nature of the original organic material, but also by environmental factors such as soil texture, redox conditions and tidal influence. In general. an increase in the humification process appeared to be related to aerobic conditions and predominance of sand in the mineral fraction of the soil, while the preservation of labile organic compounds may be associated with low redox potential values and fine soil texture. (C) 2008 Elsevier Ltd. All rights reserved.; Spanish Government[MEDC-CAPES054-03]; Spanish Government[AP2003-387]

Influência do tamanho molecular aparente das substâncias húmicas aquáticas na eficiência da coagulação com sulfato de alumínio e cloreto férrico; Influence of apparent molecular size from aquatic humic substances in the coagulation efficiency with aluminium sulfate and ferric chloride

Sloboda, Eliane
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/11/2007 PT
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46.45%
Existem muitos mananciais usados como fonte de abastecimento de água que apresentam cor verdadeira relativamente alta, devido à presença de substâncias húmicas (SH). Muitas estações de tratamento de água (ETA) apresentam problemas no processo de coagulação decorrentes da presença das SH. Com isso é necessário o uso de pré-oxidantes para reduzir a cor verdadeira da água. Quando emprega-se o cloro como oxidante ocorre a formação de subprodutos halogenados, que são prejudiciais a saúde humana. Para este estudo coletou-se água no Rio Itapanhaú - Bertioga/SP, a qual apresentou cor verdadeira na ordem de 400 uH. Para a extração das SHA empregou-se a resina XAD 8. Os extratos de SHA foram filtrados em membrana com poros de 0,45 µm e após utilizou-se a técnica de ultrafiltração (UF) para o fracionamento do material húmico em diferentes tamanhos moleculares aparente. As frações empregadas na caracterização foram: F1: menor que 0,45 µm, F2: entre 100 kDa e 0,45 µm, F3: entre 30 e 100 kDa, F4: entre 10 e 30 kDa, F5: entre 5 e 10 kDa. As frações foram caracterizadas por meio das técnicas de análise elementar, espectroscopia de ultravioleta/visível, infravermelho e ressonância magnética nuclear de 13C (RMN de 13C). Os resultados mostraram que as frações de menor tamanho molecular aparente (F3...

Ocorrência e significado paleoambiental do Horizonte A húmico em Latossolos; Occurrence and palaeenvironmental significance of humic horizon in Latosols (oxisols)

Calegari, Márcia Regina
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 17/02/2009 PT
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36.51%
A ocorrência de solos com horizonte A húmico (Ah) hiperdesenvolvido ainda é pouco entendida. Nos Latossolos com esse horizonte (Lh) ele freqüentemente é muito espesso, com baixa saturação por bases e cor escura advinda do relativamente grande acúmulo de matéria orgânica até profundidades superiores a 100 cm. Exceto para a região Sul, tais atributos estão em desconformidade com as atuais condições de clima e vegetação em que esses Lh se encontram. Objetivou-se definir variáveis ambientais que teriam influenciado na gênese desse horizonte em Latossolos, investigando-se dados de morfologia, textura, geoquímica, geomorfologia e evidências de paleoambientes. Realizou-se primeiro um estudo bibliográfico das principais características dos Lh no Brasil, em um conjunto de 39 perfis. Destes, 11 variáveis, representando atributos ambientais, químicos e granulométricos do solo foram submetidas a análises estatísticas multivariadas, para agrupá-los segundo similaridades. Três grupos foram definidos: G1 - Latossolos Brunos e Vermelhos em superfícies de cimeira da região Sul, com os mais altos teores de carbono orgânico e de Fe2O3, Ah menos espesso e mineralogia mais oxídica que os demais; G2- Latossolos Vermelho-Amarelos e Amarelos em antigas superfícies geomorfológicas da região Sudeste...

O seqüestro de carbono e as substâncias húmicas na área de influência da BR-163 - Cuiabá-Santarém; Carbon sequestration and humic substances in BR-163 influences area - Cuiabá-Santarém

Silva, Orlando Paulino da
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/09/2008 PT
Relevância na Pesquisa
36.65%
Compreender os ciclos de nutrientes e a dinâmica da matéria orgânica no ecossistema da Amazônia é essencial para o domínio do manejo eficiente da floresta e do solo. O desaparecimento de florestas tropicais, acompanhada de acelerados processos de perda de solo e de matéria orgânica, pelo desmatamento, queimadas e avanço da fronteira agrícola despertam preocupações. As características das substâncias húmicas remetem aos processos de gênese da matéria orgânica, à capacidade de sustentabilidade para os usos múltiplos em cultivos e aparece como indicador da qualidade do solo. O objetivo deste trabalho foi relacionar as características das substâncias húmicas do solo com o seqüestro de carbono em sítios de floresta em clímax, em área moderadamente e intensamente antropizada, ambientes de influência da Rodovia BR-163 - Cuiabá-Santarém, região que experimenta um incremento das ações antrópicas em função do anúncio da pavimentação desta rodovia. Foram determinadas as características das substâncias húmicas pelas técnicas de espectroscopia no infravermelho com transformada de Fourier (FTIR), análise elementar, espectroscopia de fluorescência de luz no UV/Visível, espectroscopia de absorção de luz no UV/Visível...

Influence of alkaline extraction on the characteristics of humic substances in Brazilian soils

Rosa, André Henrique; de Oliveira, L. C.; Bellin, I. C.; Rocha, J. C.; Romao, LPC; Dias, N. L.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 77-82
ENG
Relevância na Pesquisa
36.44%
An investigation was made of the influence of alkaline extraction on the characteristics of humic substances extracted from Brazilian soil samples. Humic substances (HS) from seven different soils samples collected in Brazil were extracted using the procedure recommended by the International Humic Substances Society (IHSS). Soils, HS and humins were characterized by thermogravimetry and differential thermal analysis. About 8 mg of each material (soil, HS and humin) were placed in a platinum crucible and heated continuously from 20 to 750 degrees C at a heating rate of 10 degrees C min(-1) in an atmosphere of synthetic air (100 ml min(-1)). A thermal analysis revealed a difference between the content and structural characteristics of organic matter present in HS and humin fractions in relation to their soils. The results indicated that alkaline extraction alters the characteristics of humic substances during the extraction process, underlining the importance of developing methodologies and analytical procedures that allow organic matter in soils to be studied without extracting it. (c) 2005 Elsevier B.V. All rights reserved.

Humic acid production by fermentation of waste from palm oil processing using Trichoderma strains = : Produção de ácidos húmicos por fermentação de resíduos do processamento de óleo de palma utilizando cepas de Trichoderma; Produção de ácidos húmicos por fermentação de resíduos do processamento de óleo de palma utilizando cepas de Trichoderma

Fernanda Lopes Motta
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 26/07/2013 PT
Relevância na Pesquisa
36.38%
Ácidos húmicos (AH) são macromoléculas orgânicas de alta complexidade estrutural. Na agricultura, seus efeitos diretos na produtividade e na qualidade de diversos cultivos têm sido explorados desde 1940 e na última década houve um grande crescimento no seu emprego na medicina e na biologia. Embora suas inúmeras aplicações tenham atraído a atenção de muitos pesquisadores, os AH comerciais são ainda extraídos da turfa e do carvão mineral, fontes não renováveis de carbono, indicando a necessidade do desenvolvimento de um processo biotecnológico para sua produção. Empty-fruit-bunches (EFB) são resíduos do processamento do óleo de palma subutilizados ou descartados. Além disso, EFB são fibras constituídas de celulose, hemicelulose e lignina, cuja degradação pode ser alcançada por meio da ação de micro-organismos com alta capacidade de degradação de material lignocelulósico, como o Trichoderma. Neste contexto, este trabalho visou produção de AH a partir da fermentação de EFB com cepas de Trichoderma. Os resultados obtidos demonstraram que aveia é um substrato adequado para produção de esporos de Trichoderma em profundidade para sua aplicação como inóculo das fermentações submersas (FS) de EFB para produção de AH. A investigação dos precursores dos AH dentre os polímeros constituintes do EFB indicaram um efeito sinergético destes polímeros. Quanto à substituição do extrato de leveduras por peptonas vegetais nos meios de cultivo...

Modelling of biofilm growth on humic substances

Martins, Gilberto; Rodrigues, A. L.; Brito, A. G.; Nogueira, R.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /11/2007 ENG
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36.15%

Characterization of biofilm formation on a humic material

Rodrigues, A. L.; Brito, A. G.; Janknecht, P.; Inácio, J.; Machado, A. V.; Nogueira, R.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em 28/11/2007 ENG
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46.25%

Characterization of biofilm formation on a humic material

Rodrigues, A. L.; Brito, A. G.; Janknecht, P.; Silva, J.; Machado, A. V.; Nogueira, R.
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em /11/2008 ENG
Relevância na Pesquisa
56.38%
Biofilms are major sites of carbon cycling in streams. Therefore, it is crucial to improve knowledge about biofilms’ structure and microbial composition to understand their contribution in the self-purification of surface water. The present work intends to study biofilm formation in the presence of humic substances (HSs) as a carbon source. Two biofilm flowcells were operated in parallel; one with synthetic stream water, displaying a background carbon concentration of 1.26 ± 0.84 mg L−1, the other with added HSs and an overall carbon concentration of 9.68 ± 1.00 mg L−1. From the biofilms’ results of culturable and total countable cells, it can be concluded that the presence of HSs did not significantly enhance the biofilm cell density. However, the biofilm formed in the presence of HSs presented slightly higher values of volatile suspended solids (VSS) and protein. One possible explanation for this result is that HSs adsorbed to the polymeric matrix of the biofilm and were included in the quantification of VSS and protein. The microbial composition of the biofilm with addition of HSs was characterized by the presence of bacteria belonging to beta-Proteobacteria, Cupriavidus metallidurans and several species of the genus Ralstonia were identified...

Elemental and spectral properties of peat and soil samples and their respective humic substances

Fernandes, Andreia Neves; Giovanela, Marcelo; Esteves, Valdemar Inocencio; de Souza Sierra, Maria Marta
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
36.43%
In this study, peat and soil samples, as well as their respective humic substances (HS), were investigated through the techniques of elemental analysis. Fourier transform infrared/attenuated total reflectance (FTIR/ATR) spectroscopy and solid state (13)C nuclear magnetic resonance with cross-polarization/magic angle spinning (CP/MAS (13)C NMR) techniques. The data showed that, particularly in the case of peat, almost all of the signals relating to the presence of typical chemical groups of natural organic material (OM) were found in both the raw samples and in the HS extracted from them, being, in general, better defined in the latter. The combined information reinforces the role of HS as major representatives in natural OM. The differences observed before and after extraction, which were more evident for the soils, were attributed to the strong presence of mineral material and, consequently, low concentration of organic material in the raw samples, weakening and masking the signals usually emitted by OM. (C) 2010 Elsevier B.V. All rights reserved.

Possible disruption of pheromonal communication by humic acid in the goldfish, Carassius auratus

Barata, Eduardo N.
Fonte: Universidade de Évora Publicador: Universidade de Évora
Tipo: Artigo de Revista Científica Formato: 621568 bytes; application/pdf
ENG
Relevância na Pesquisa
36.55%
Humic acids are large, complex, organic molecules which are ubiquitous components of aquatic environments as products of degradation of plant material. In aqueous solution they form microvesicles. As many teleost pheromones are steroidal in nature, we hypothesised that they would preferentially dissolve in the organic, hydrophobic core of these vesicles instead of in water and therefore be unavailable for detection. This would have obvious and profound effects on many aspects of fish biology. To test this hypothesis we recorded electro-olfactogram (EOG) response of the goldfish (Carassius auratus) olfactory epithelium to the pheromones 17alpha,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P), its sulphated conjugate (17,20beta-P-SO4) and prostaglandin F-2alpha (PGF(2alpha)), all at 10(-11) to 10(-8) M, in the absence and presence of humic acids (1-1000 mg l(-1)). At nearly all concentrations of humic acid tested, there was a significant attenuation of the amplitude of the initial (phasic) response to 17,20beta-P compared to 17,20beta-P alone. At higher concentrations of humic acid, the EOG response to 17,20beta-P was often completely obliterated, suggesting that the concentration of the pheromone available to the olfactory epithelium was below the threshold of detection. Exposure of the olfactory epithelium to humic acid did not cause any short-term loss of sensitivity to 17...

Synchronous-scan fluorescence and the complexation of copper (II) ions by humic substances

Lombardi,Ana T; Jardim,Wilson F
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/1997 EN
Relevância na Pesquisa
36.27%
Two fluorescence bands were detected using synchronous-scan fluorescence on samples of terrestrially derived humic substances (lex/lem 380/398, 440/458 nm) without the addition of copper. A third band (lex/lem 502/520 nm) was detected after severe quenching of the second band (lex/lem 440/458 nm) caused by additions of copper. A more energetic band (lex/lem 333/351 nm) is present in marine DOM, but absent in the terrestrial material. The effects of copper on both the intensity and shape of the synchronous-scan fluorescence spectra and this technique’s potential use as a tracer are discussed.

Estimation of Uptake of Humic Substances from Different Sources by Escherichia coli Cells under Optimum and Salt Stress Conditions by Use of Tritium-Labeled Humic Materials▿

Kulikova, Natalia A.; Perminova, Irina V.; Badun, Gennady A.; Chernysheva, Maria G.; Koroleva, Olga V.; Tsvetkova, Eugenia A.
Fonte: American Society for Microbiology (ASM) Publicador: American Society for Microbiology (ASM)
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
36.35%
The primary goal of this paper is to demonstrate potential strengths of the use of tritium-labeled humic substances (HS) to quantify their interaction with living cells under various conditions. A novel approach was taken to study the interaction between a model microorganism and the labeled humic material. The bacterium Escherichia coli was used as a model microorganism. Salt stress was used to study interactions of HS with living cells under nonoptimum conditions. Six tritium-labeled samples of HS originating from coal, peat, and soil were examined. To quantify their interaction with E. coli cells, bioconcentration factors (BCF) were calculated and the amount of HS that penetrated into the cell interior was determined, and the liquid scintillation counting technique was used as well. The BCF values under optimum conditions varied from 0.9 to 13.1 liters kg−1 of cell biomass, whereas under salt stress conditions the range of corresponding values increased substantially and accounted for 0.2 to 130 liters kg−1. The measured amounts of HS that penetrated into the cells were 23 to 167 mg and 25 to 465 mg HS per kg of cell biomass under optimum and salt stress conditions, respectively. This finding indicated increased penetration of HS into E. coli cells under salt stress.

Molecular characterization of Cladium peat from the Florida Everglades: biomarker associations with humic fractions

Hajje, Neghie; Jaffe´, Rudolf
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
36.46%
The accumulation and preservation of peat soils in Everglades freshwater marshes and mangrove swamps is an essential process in the ecological functioning of these ecosystems. Human intervention and climate change have modified nutrient dynamics and hydroperiod in the Everglades and peat loss due to such anthropogenic activities is evident. However, not much is known on the molecular level regarding the biogeochemical characteristics, which allow peat to be preserved in the Everglades. Lipid biomarkers trapped within or bound to humic-type structures can provide important geochemical information regarding the origin and microbial transformation of OM in peat. Four lipid fractions obtained from a Cladium peat, namely the freely extractable fraction and those associated with humin, humic acid, and fulvic acid fractions, showed clear differences in their molecular distribution suggesting different OM sources and structural and diagenetic states of the source material. Both, higher plant derived and microbial lipids were found in association with these humic-type substances. Most biomarker distributions suggest an increment in the microbial/terrestrial lipid ratio from the free to humin to humic to fulvic fractions. Microbial reworking of lipids...

As-mineral-humic substance interactions - Influence of natural organic matter on sorption and mobility of As; As-Mineral-Huminstoff-Interaktionen - Einfluss von natürlichem organischen Material auf Sorption und Mobilität von As

Sharma, Prasesh
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
EN
Relevância na Pesquisa
36.51%
The geochemistry of As is strongly affected by the presence of natural organic matter (NOM) and minerals. NOM can change As speciation via redox reactions and complexation. In chapter 2, we showed the formation of binary and ternary colloids and dissolved complexes of As(V), Fe and OM by ATR-FTIR and Mössbauer-spectroscopy. Dissolved Fe-OM complexes and ferrihydrite-OM colloids were formed by reacting OM with ferrihydrite (Fe(OH)3). Mössbauer spectroscopy showed that about 5% of the Fe in the colloidal ferrihydrite-OM mixture was present as Fe-OM complexes in the dissolved fraction. In As(V) plus Fe-OM systems (containing both dissolved and colloidal Fe-OM), 3.5-8 my g As(V)/mg OC was bound to the Fe-OM complexes/colloids compared to <0.015 my g As(V)/mg OC in As-OM systems (without Fe). Upon filtration of As-Fe-OM complexes/colloids with a 3 kDa filter, about 6% As was found in the dissolved fraction and about 94% As in colloidal Fe-OM. Results suggest that As(V) is associated with Fe-OM mainly via ferrihydrite-OM colloids but to a small extent also in dissolved Fe-OM complexes via Fe-bridging. In Chapter 3 and 4, column experiments were used to study the effect of NOM on As transport and retention in ferrihydrite-coated sand systems. OM containing systems transported As faster and also desorbed As to a higher extent than in OM-free systems. Between As(III) vs. As(V)...

DISSOLVED ORGANIC CARBON FACILITATED TRANSPORT OF NEUTRAL ORGANIC COMPOUNDS IN SUBSURFACE SYSTEMS (GROUNDWATER, HUMIC, ADSORPTION)

WEST, CANDIDA COOK
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Thesis; Text Formato: application/pdf
ENG
Relevância na Pesquisa
36.45%
A ground water humic material has been isolated using XAD-8 adsorption chromatography (Thurman and Malcolm, 1981). Partitioning studies for DDT, hexachlorobenzene (HCB), and bis(2-ethylhexyl)phthalate (BEHP) and soil column studies for HCB and anthracene have been completed. Partition coefficients for DDT, HCB and BEHP are 10('5.99), 10('4.64) and 10('3.66), respectively. A linear relationship between log solubility (mole fraction) and log partition coefficient (Kp) exists where: log Kp = -0.91 log S (mole fraction) -3.34 (R = 0.9984). These values are in agreement with those determined for soil sediments for compounds whose water solubilities are in the range of 1 (mu)g-l('-1), but are lower by an order of magnitude for compounds whose water solubilities are on the order of 500 (mu)g-l('-1) (Karickhoff, 1979). The classical contaminant retardation equation was modified to account for mediated transport by dissolved organic carbon (DOC). Soil column experiments exhibited mediated transport of HCB and anthracene by the humic material and provided strong evidence that the compounds move as an irreversible humic/organic complex. The implications and magnitude of this mediation of organic transport by ground water humics is discussed. The existence of such a complex may account for the enhanced migration of certain trace level organics in ground water.

Growth promotion of pineapple 'vitória' by humic acids and burkholderia spp. during acclimatization

Baldotto,Lílian Estrela Borges; Baldotto,Marihus Altoé; Canellas,Luciano Pasqualoto; Bressan-Smith,Ricardo; Olivares,Fábio Lopes
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2010 EN
Relevância na Pesquisa
36.5%
In vitro propagation of pineapple produces uniform and disease-free plantlets, but requires a long period of acclimatization before transplanting to the field. Quicker adaptation to the ex vitro environment and growth acceleration of pineapple plantlets are prerequisites for the production of a greater amount of vigorous, well-rooted planting material. The combination of humic acids and endophytic bacteria could be a useful technological approach to reduce the critical period of acclimatization. The aim of this study was to evaluate the initial performance of tissue-cultured pineapple variety Vitória in response to application of humic acids isolated from vermicompost and plant growth-promoting bacteria (Burkholderia spp.) during greenhouse acclimatization. The basal leaf axils were treated with humic acids while roots were immersed in bacterial medium. Humic acids and bacteria application improved shoot growth (14 and 102 %, respectively), compared with the control; the effect of the combined treatment was most pronounced (147 %). Likewise, humic acids increased root growth by 50 %, bacteria by 81 % and the combined treatment by 105 %. Inoculation was found to significantly increase the accumulation of N (115 %), P (112 %) and K (69 %) in pineapple leaves. Pineapple growth was influenced by inoculation with Burkholderia spp....

Reaction products of aquatic humic substances with chlorine.

Johnson, J D; Christman, R F; Norwood, D L; Millington, D S
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /12/1982 EN
Relevância na Pesquisa
36.5%
A major concern of the chlorination of aquatic humic materials is the ubiquitous production of trihalomethanes. A large number of other chlorinated organic compounds, however, have been shown to be formed by chlorine's reaction with humic substances. In this study, humic material was concentrated from a coastal North Carolina lake and chlorinated at a chlorine to carbon mole ratio of 1.5 at pH 12. A high pH was necessary for complete dissolution of the humic material and for production of adequate quantities of oxidation and chlorination products for extraction, separation and mass spectrometric identification. After concentration in ether, samples were methylated, separated with a 50-m OV-17 glass capillary column or a 25 m SP-2100 fused-silica column and identified. A Hewlett-Packard 5710A gas chromatograph interfaced to a VG Micromass 7070F double-focusing mass spectrometer was used. Low resolution, accurate mass measurements were made with a combined EI-Cl source. The ability to do low resolution, accurate mass measurements made possible a rapid scan function necessary for capillary column gas chromatography. Accurate mass measurements allowed increased confidence in the identification of compounds, most of which are not available as standards. The products identified in these studies were chlorinated aliphatic straight-chain acids dominated by di- and trichloroacetic acid and the chlorinated dicarboxylic acids: succinic...

Chemical-structural characterization of solvent and thermal extractable material from perhydrous vitrinites

Iglesias, María José; Río Andrade, José Carlos del; Laggoun-Défarge, Fatima; Cuesta, María José; Suárez Ruiz, Isabel
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 292130 bytes; application/pdf
ENG
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In this work, the characterization of the non-covalently bonded compounds present in a set of perhydrous coals of different age and geographical location (Cretaceous coals: UCV and TCV and Jurassic coals: AJV, PGJV, WJVh and WJVl) was carried out by means of a combination of the analyses of the material soluble in chloroform and the thermal extract. The extract in chloroform was studied through GC/MS and NMR and the thermovaporized fraction was obtained by means of flash pyrolysis at the Curie temperature of 350°C and quantified by on-line GC-MS. The results obtained for the Cretaceous coals confirm that the substances responsible for the hydrogenation are those covalently bonded to the vitrinite network as a result of the modifications undergone by the botanical precursors. Despite the striking similarity in the global characteristics of these two coals (TCV and UCV) significant differences between the material non-covalently bonded to their coal matrices were found. These differences are attributed to the type of resins present in the coals and/or to their different degree of evolution. With respect to the Jurassic coals, the present study allows the process by which the hydrogenated substances were assimilated into their structure to be established. The characterization of the assimilated substances in the WJVl coal reveals an unexpectedly high incorporation of alkanes given the humic origin of this sample. From these results the assimilation of hydrogen-rich substances from the decomposition of the organic remains in the sedimentary environment in which WJVl precursor were deposited...